The present invention relates to controlling the treatment of air for the inside of a building and especially to controlling a hybrid air conditioning system for the regulation of the air temperature and humidity utilizing independently operative air conditioning units of differing capacity and an independently operative dehumidifier to control indoor air conditions.
The present invention is in the technical field of air treatment for inside air comfort and indoor air quality. More particularly, the present invention is in the technical fields of ventilation, cleaning, cooling, heating, and humidity treatment of inside air. More particularly, the present invention is in the technical fields of equipment and controls for performing inside air comfort and air quality treatments of inside air. The conventional “central air conditioning system” is generally a single unit of a fixed or restricted capacity sized as the largest machine required to cool down a building's interior air on the hottest of days with the highest of heat loads within a relatively short time period. This high level of capacity and power use is typically only needed for approximately one third of the year, meaning that the equipment is over-sized and using more energy than needed to condition interior air for the remaining two-thirds of the year, resulting in problems such as energy wasting overcooling and “reheats” to control humidity. Inside air treatment needs shift during this “off-season” two-thirds period from the priority function of high heat control by the central air conditioner to that of a need for smaller cooling capacities or for alternate air treatment needs such as control of humidity levels. In these situations, smaller cooling capacity equipment (such as a window unit) or a unit dedicated to a specific function, such as humidity control, can provide superior inside air treatment at significantly lower energy use and costs to the consumer.
What is needed in order to optimally comfort condition inside air at the lowest energy inputs and costs is a process control that can match specific air comfort conditioning treatments to the optimum size and type equipment designed to best handle each task, using the lowest power consumption by flexibly matching units to changing conditions. With a conventional central air conditioning system, the installation is generally the largest machine needed to cool down a buildings interior air, on the hottest of days with the highest of heat loads, within the relatively short time period necessary to achieve acceptable comfort. This high level of air conditioning power use however is typically only needed for a part of the year, meaning that the equipment is over-sized and uses more energy than needed to comfort condition interior air for the remaining two-thirds of the year. In addition, the air comfort and air quality treatment needs shift from the primary function of heat control by the central air conditioner in summer months to that of controlling other factors, such as humidity, when air temperatures are moderate or mild during fall and spring periods but humidity levels can build up because the cooling function of the air conditioner is not being activated for direct cooling (salient heat removal) of the interior air so as to also indirectly remove water vapor by condensation (latent heat removal) to lower the humidity. In such an example, the invention herein described would detect the increase in humidity level and activate the dedicated dehumidifier to dehumidify the air without running the larger air conditioner which would also lower the air temperature, often to a level where a “reheat” function is needed to raise the air temperature back up to the Set comfort level, wasting energy. Similarly, using a smaller air conditioner to cool condition low air heat demands, allows the smaller machine to operate more continuously at its Optimum design performance—running steadily and efficiently and effectively at a constant rate instead of over-cooling quickly and shutting on and off continuously. With oversized capacity on undersized loads, machine life suffers and breakdowns increase from the constant stops and start short run times of the oversized unit, and with such cycling comfort is compromised while energy is wasted as each cycle consumes considerable more energy than that of a longer running unit that matches the prevailing cooling demands.
A hybrid air conditioning system having plural separate air conditioning units and a separate dehumidifier in the present invention are controlled in a process to provide superior air treatment for inside air comfort while allowing user tradeoffs for priority control of either energy saving or more personal comfort.